Cerebral amyloid angiopathy (CAA) is characterized by the accumulation of Aβ proteins primarily within the media and adventitia of small arteries and capillaries in the cortex and leptomeninges. About 85% of AD patients and many individuals over 60 years of age manifest CAA (Ellis, Olichney et al. 1996). Due to the lack of early diagnostic agents or biomarkers, a probable CAA diagnosis is often reached through cortical biopsies after the patient has sustained multiple lobar hemorrhages (Greenberg and Vonsattel 1997, Sakaguchi, Ueda et al. 2011). Due to sampling variability, even cortical biopsy is not specific enough to distinguish between the pathological accumulation of cerebrovascular amyloid deposits found in CAA patients and the vascular amyloid seen in normal aged brain. Hence, a definitive CAA diagnosis can currently be reached only post-mortem (Thanvi and Robinson 2006).
In addition to challenges associated with the early diagnosis, the treatment options for CAA are very few and mostly ineffective. In a sub-class of CAA patients, however, chronic treatment with immunosuppressants, like cyclophosphamide and methylprednisolone, offer symptomatic relief from cerebrovascular inflammation (Eng, Frosch et al. 2004). However, immunosuppressants exhibit systemic toxicity and severe side effects that have the potential of being worse than the disease itself. Moreover, immunosuppressant therapy does not address the underlying pathology of the disease, which is triggered by the anamolous accumulation of amyloid proteins in the cerebral vasculature.